* {
    margin: 0;
    padding: 0;
    text-decoration: none;
    list-style: none;
}

.app {
    width: 700px;
    height: 600px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: #cccccc;
    border: 1px black solid;
}

.titleContainer {
    height: 100px;
    line-height: 100px;
    text-align: center;
    border-bottom: 1px black solid;
}

.container {
    height: 500px;
}

.navContainer {
    height: 500px;
    width: 99px;
    text-align: center;
    border-right: 1px black solid;
    float: left;
}

.mainContainer {
    display: inline-block;
    height: 500px;
}